Composition With Improved Cleanliness For Lubrication Of Steam And Gas Turbine Systems

ABSTRACT

The present invention relates to the use of an additive composition that contains the combination of two specific types of antioxidants with one or more of four specific types of dispersants in a Group II and/or Group III base oil-containing lubricating composition. The lubricating composition of the present invention provides improved cleanliness in steam and gas turbine systems. The invention further relates to the process to make the novel additive composition and its use in industrial fluids.

FIELD OF THE INVENTION

The present invention relates to the use of an additive composition thatcontains the combination of two specific types of antioxidants with oneor more of four specific types of dispersants in a Group II and/or GroupIII base oil-containing lubricating composition. The lubricatingcomposition of the present invention provides improved cleanliness insteam and gas turbine systems. The invention further relates to theprocess to make the novel additive composition and its use in industrialfluids.

BACKGROUND OF THE INVENTION

Varnish is a well known and recognized problem in the lubricant industryand in the area of power generation and gas-turbine applications isbecoming of greater and greater concern. Turbine design is moving tosystems that provide more power from smaller equipment, leading totighter clearances, extended drain intervals, and so more stress andharsher conditions on both the equipment and the lubricant used in itsoperation. The best fluids will meet these challenges and keep thesystem free of varnish and other deposits. In addition turbine oils areincreasingly being formulated with Group II and Group III oils insteadof Group I base oils.

These new base oils are much less polar than Group I oils, and additiveformulations that worked well in Group I base oils often fail to providethe desired performance when used in Group II and Group III oils.Coupled with the design and operation changes discussed above, there isa need to tailor the additive mixture for optimum performance in GroupII and/or Group III base oils.

Group II and Group III oils are more highly refined than Group I oils.Group I oils tend to have higher aromatic and unsaturated components,which are more susceptible to oxidation than other species found in theoils. Indeed, these new groups of oils were developed in part to try andprovide improved oxidation stability. While this does provide improvedoxidative stability for the base oil itself, they also end up havingpoorer solvency compared to Group I oils. With this reduced solvency,oxidation by-products, from the oil itself or other sources, that wouldhave remained dissolved in Group I based fluids often drop out of GroupII or Group III based fluids, forming varnish on the surfaces of theequipment.

In addition, many power generation turbines in today's market arepeaking units, meaning they only operate at times of peak demand. Duringthe regular periods of down time in this type of equipment, when thesystem lubricant cools, solvency decreases allowing polar materials andvarnish to come out of solution and deposit on metal surfaces.

In addition to oxidation and the by-products it produces, staticdischarge, micro-dieseling, incompatibility, and contamination are alsoroot causes of varnish. Incompatibility is a particular concern withGroup II and Group III oils as some additives that are compatible withGroup I oils are not compatible with Group II and Group III oils.

Furthermore, Group I based fluids tend to follow gradual oxidation ratesthat can be monitored over time, giving operators a reliable means ofdetermining the remaining service life of a fluid. In contrast, Group IIand Group III based fluids may go from normal oxidation levels andoperation to failure mode very quickly with little or no indicationbefore hand. This added complication further increases the need forGroup II and Group III based fluids that provide reliable performance inthese high cost systems that cannot afford unplanned downtime andequipment damage caused by spent lubricant.

Formulating a fluid with the required amount of oxidative stability andresistance to formation of deposits is a challenge. The primary types ofadditives used to control oxidation are phenols and amines, both ofwhich react at high temperatures, forming oxidation products thatcontribute to system deposits and varnish. Thus it is critical to findthe proper balance of oxidation inhibitor and dispersant components forthe specific application and base fluid involved, allowing forsignificantly improved lubricant life, and so equipment life andoperation time. Dispersants frequently cause oil and water to emulsify,so the choice of the right dispersant must allow the fluid to maintaingood demulsibility as required for proper turbine operation. Emulsifiedwater reduces lubricant film formation and promotes rust and oxidation.Fluids that emulsify are not widely accepted in the marketplace.

The formulation of lubricating compositions for steam and gas turbinesystems has been complicated by the growing use of API Group II andGroup III base oils which has led to increasing varnish formation insome power generating turbines. There is a need for turbine lubricantsthat allow the use of Group II and Group III base oils while providinglong service life, that avoid the varnish problems that can lead todisruptions in equipment operation and unplanned downtime.

It would be desirable for these lubricating oil compositions to becapable of imparting acceptable levels of rust and/or oxidationinhibition without the formation of unwanted deposits that increase theviscosity of the fluid. Furthermore, it would be desirable for theselubricating oil compositions to control and prevent the formation offilter plugging deposits and/or sludge in industrial fluids.

SUMMARY OF THE INVENTION

The invention provides Group II and Group III base oil formulatedlubricating compositions for steam and gas turbine systems that providebalanced performance in modern turbine systems. The invention furtherprovides a method of making such compositions and methods of using themin the operation of steam and gas turbine systems.

The invention provides a lubricating oil composition made up of: (a) anoil of lubricating viscosity that includes a Group II base oil, a GroupIII base oil, or combinations thereof; (b) an antioxidant component; and(c) a dispersant component. The antioxidant component includes: (i) analkylated diphenylamine, and (ii) a substituted hydrocarbylmono-sulfide. The dispersant component includes: (i) a polyetheramine;(ii) a borated succinimide dispersant; (iii) a non-borated succinimidedispersant; (iv) a Mannich reaction product of a dialkylamine, analdehyde and a hydrocarbyl substituted phenol; or any combinationthereof. The compositions of the present invention may also include oneor more additional additives.

The invention further provides for compositions that further include:(i) a rust inhibitor, for example an amine phosphate, a fatty carboxylicacid or ester thereof, an ester of a nitrogen-containing carboxylicacid, an ammonium sulfonate, or an imidazoline; (ii) a metaldeactivator, for example a triazole, a tolyltriazole, a thiadiazole, orcombinations thereof; (iii) a demulsifier, for example a polyether; (iv)an antifoam agent, for example an acrylate copolymer; or anycombinations thereof.

The invention further provides for compositions that include asubstituted hydrocarbyl mono-sulfide. In other embodiments the inventionprovides for compositions essentially free or even free of substitutedhydrocarbyl mono-sulfides.

The invention provides for the compositions described above where thedispersant component includes a polyetheramine derived from the reactionof a mixture of alcohols containing from 10 to 18 carbon atoms, analkylene oxide and an amine; wherein the antioxidant component ispresent in the overall composition at less than 0.865 parts by weight;wherein the composition is free of N-alkyl sarcosines; wherein thecomposition contains less than 0.1 parts by weight of fatty carboxylicacids; and wherein the dispersant component is present in the overallcomposition from 0.07 to 0.4 parts by weight.

The invention provides for the compositions described above where thedispersant component includes a borated succinimide dispersant derivedfrom polyisobutylene having a number average molecular weight from 500to 3000 and polyethylenepolyamines; wherein the dispersant component ispresent in the overall composition from 0.07 to less than 0.4 parts byweight.

The invention provides for the compositions described above where thedispersant component includes a non-borated succinimide dispersantderived from polyisobutylene having a number average molecular weightfrom 500 to 3000 and polyethylenepolyamines; wherein the compositioncontains less than 0.1 parts by weight of fatty carboxylic acids; andwherein the dispersant component is present in the overall compositionfrom 0.06 to 0.35 parts by weight.

The invention provides for the compositions described above where thedispersant component includes a Mannich reaction product derived fromthe reaction of a dialkylamine, formaldehyde, and a polyisobutylenesubstituted phenol where the polyisobutylene has a number averagemolecular weight from 500 to 3000; and wherein the dispersant componentis present in the overall composition from 0.07 to 0.44 parts by weight.

The process of the invention, wherein the antioxidant package is in therange of 0.05 to 13 parts be weight of the overall composition; thedispersant component is in the range of 0.05 to 10 parts be weight ofthe overall composition; the optional additives, when present, arepresent from 0.001 to 10 parts be weight of the overall composition; andthe balance is made up of the oil of lubricating viscosity.

The invention provides for a process of making the lubricatingcompositions described herein including the steps of mixing together thecomponents described above, and further described below.

The invention further provides a lubricating oil composition that iscapable of preventing filter plugging deposits and sludge.

DETAILED DESCRIPTION OF THE INVENTION

Various features and embodiments of the invention will be describedbelow by way of non-limiting illustration. Unless otherwise noted, thepart by weight (pbw) values provided herein for various componentsdescribed below are in regards to compositions that contain 100 pbw baseoil. However the pbw values may, in some embodiments, instead be treatedas percent by weight values relative to an overall composition.

The invention provides a lubricating oil composition made up of: (a) anoil of lubricating viscosity that includes a Group II base oil, a GroupIII base oil, or combinations thereof; (b) an antioxidant component; and(c) a dispersant component. The antioxidant component includes: (i) analkylated diphenylamine, and (ii) a substituted hydrocarbylmono-sulfide. The dispersant component includes: (i) a polyetheramine;(ii) a borated succinimide dispersant; (iii) a non-borated succinimidedispersant; (iv) a Mannich reaction product of a dialkylamine, analdehyde and a hydrocarbyl substituted phenol; or any combinationthereof. The compositions of the present invention may also include oneor more additional additives.

The Oil of Lubricating Viscosity

One component of the compositions of the invention is an oil oflubricating viscosity, which can be present in a major amount, for alubricant composition, or in a concentrate forming amount, for aconcentrate. Suitable oils include natural and synthetic lubricatingoils and mixtures thereof. In a fully formulated lubricant, the oil oflubricating viscosity is generally present in a major amount (i.e. anamount greater than 50 percent by weight). Typically, the oil oflubricating viscosity is present in an amount of 75 to 95 percent byweight, and often greater than 80 percent by weight of the overallcomposition. The base oil component generally makes up 100 parts byweight (pbw) of the overall composition with the pbw ranges for theother components being provided with this 100 pbw of base oil in mind.In other embodiments the pbw ranges of the various components, includingthe base oils, are provided such that the total of the pbw of allcomponents is 100. The pbw ranges provided for the various componentsdescribed below may be taken either way.

The lubricating oil component of the present invention includes a GroupII or Group III base oil, or a combination thereof. These areclassifications established by the API (American Petroleum Institute).Group III oils contain<0.03 percent sulfur and >90 percent saturates andhave a viscosity index of >120. Group II oils have a viscosity index of80 to 120 and contain<0.03 percent sulfur and >90 percent saturates. Theoil can also be derived from the hydroisomerization of wax, such asslack wax or a Fischer-Tropsch synthesized wax. Such “Gas-to-Liquid”oils are typically characterized as Group III.

The compositions of the present invention may include some amount ofGroup I base oils, and even Group IV and Group V base oils.Polyalphaolefins are categorized as Group IV. Group V encompasses “allothers”. However, in some embodiments the lubricating oil component ofthe invention contains no more than 20, 10, 5, or even 1 percent byweight Group I base oil. These limits may also apply to Group IV orGroup V base oils. In other embodiments the lubricating oil present inthe compositions of the invention is at least 60, 70, 80, 90, or even 95percent by weight Group II and/or Group III base oil. In someembodiments the lubricating oil present in the compositions of theinvention is essentially only Group II and/or Group III base oil, wheresmall amounts of other types of base oils may be present but not inamounts that significantly impact the properties or performance of theoverall composition.

The oil of lubricating viscosity may be present in the range from 60 to99.9, from 88.5 to 99.6, from 96.9 to 99.5, or from 98.2 to 99.4 weightpercent of the lubricating oil composition. Each oil of lubricatingviscosity described above may be used alone or as mixtures of one ormore thereof.

The Antioxidant Component

The antioxidant component includes: (i) an alkylated diphenylamine, and(ii) a substituted hydrocarbyl mono-sulfide.

The alkylated diphenylamines suitable for use in the invention may berepresented by the formula:

wherein R¹ and R² are independently a hydrogen or an alkyl groupcontaining about 5 to 20 carbon atoms; or a linear or branched alkylgroup containing 1 to 24 carbon atoms and q and r are each independently0, 1, 2, or 3, provided that the sum of q and r is at least one. In someembodiments R¹ and R² are independently hydrogen or alkyl groupscontaining 1 to 24, 4 to 20, 5 to 16, or 6 to 12 or even 10 carbonatoms. In any of the embodiments described above, each R¹ and R² may bea linear alkyl group, a branched alkyl group, or even an arylalkylgroup.

In some embodiments the alkylated diphenylamines of the invention arebis-nonylated diphenylamine and bis-octylated diphenylamine.

The alkylated diphenylamines are present in a range from 0.02 to 4, from0.03 to 2.5, or from 0.05 to 1.5 pbw of the overall lubricatingcomposition. In some embodiments the alkylated diphenylamines arepresent in a range from 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.3, or even0.35 up to 1.0, 0.9, 0.8, 0.75, 0.7, or even 0.6 pbw of the overalllubricating composition. In still other embodiments the alkylateddiphenylamines may be present from 0.35 or 0.375 up to 0.51, 0.75, 0.775or 0.1 pbw of the overall lubricating composition, or even 0.375 pbw.The alkylated diphenylamines may be used alone or in mixtures thereof.

The substituted hydrocarbyl mono-sulfides suitable for use in theinvention may be represented by the formula:

wherein R³ is a saturated or unsaturated branched or linear alkyl groupwith about 8 to about 20 carbon atoms; R⁴, R⁵, R⁶ and R⁷ areindependently hydrogen or alkyl containing about 1 to about 3 carbonatoms, or even 1 to 2 carbon atoms. In some embodiments R³ contains from8 to 20, 9 to 17, 10 to 15 or even 11 to 13 carbon atoms. R³ can bebranched or linear, but in some embodiments is branched.

In some embodiments the substituted hydrocarbyl monosulfides includen-dodecyl-2-hydroxyethyl sulfide, 1-(tert-dodecylthio)-2-propanol, orcombinations thereof. In some embodiments the substituted hydrocarbylmonosulfide is 1-(tert-dodecylthio)-2-propanol.

The substituted hydrocarbyl monosulfides may be present in the rangefrom 0.02 to 4, 0.03 to 2.5, or 0.05 to 1.5 pbw of the lubricating oilcomposition. In some embodiments the substituted hydrocarbylmonosulfides are present in a range from 0.01, 0.03, 0.05, or even 0.08up to 1.0, 0.8, 0.5, 0.3 or 0.1 pbw of the overall lubricatingcomposition. In still other embodiments the substituted hydrocarbylmonosulfides may be present from 0.08 up to 0.1, or even at 0.09 pbw ofthe overall lubricating composition. The substituted hydrocarbylmonosulfides may be used alone or mixtures thereof.

The antioxidant package may optionally include sterically hinderedphenols represented by the formula:

wherein R⁸ and R⁹ are independently branched or linear alkyl groupscontaining about 1 to about 24, preferably about 4 to about 18, and mostpreferably from about 4 to about 12 carbon atoms.

R⁸ and R⁹ may be either a straight or branched chain, branched ispreferred. Preferably the phenol is butyl substituted containing twot-butyl groups. When the t-butyl groups occupy the 2,6-positions, thephenol is sterically hindered. q is hydrogen or hydrocarbyl. Examples ofsuitable hydrocarbyl groups include but are not limited to 2-ethylhexylor n-butyl ester, dodecyl or mixtures thereof.

Other optional sterically hindered phenols suitable for the inventioninclude but are not limited to those represented by the formulae:

wherein R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵ are either straight or branchedchain and contain about 4 to about 18, preferably from about 4 to about12 carbon atoms. Preferably the phenol is butyl substituted.

R¹⁶ and R¹⁷ are independently hydrogen, an arylalkyl group or a linearor branched alkyl group. R¹⁶ and R¹⁷ are preferably in the paraposition. The arylalkyl or alkyl groups contain about 1 to about 15,preferably about 1 to about 10, and most preferably about 1 to about 5carbon atoms. The bridging group Y includes but is not limited to —CH₂—(methylene bridge) or —CH₂OCH₂— (ether bridge).

Examples of methylene-bridged sterically hindered phenols include butare not limited to 4,4′-methylenebis(6-tert-butyl o-cresol),4,4′-methylenebis(2-tert-amyl-o-cresol),2,2′-methylenebis(4-methyl-6-tert-butylphenol),4,4′-methylene-bis(2,6-di-tertbutylphenol) or mixtures thereof.

In one embodiment the antioxidant is a hindered ester-substituted phenolrepresented by the formula:

wherein R¹⁸, R¹⁹ and R²⁰ are straight or branched alkyl group containingabout 2 to about 22, preferably about 2 to about 18, more preferablyabout 4 to about 8 carbon atoms. Specific examples include but are notlimited to alkyl groups such as 2-ethylhexyl or n-butyl ester, dodecylor mixtures thereof.

The sterically hindered phenols are present in the range from 0 to 13,from 0.02 to 4, from 0.03 to 2.5, or from 0.05 to 1.5 pbw of thelubricating oil composition. The sterically hindered phenols may be usedalone or in combination. In some embodiments the compositions of theinvention are essentially free or even free of sterically hinderedphenols.

In some embodiments the antioxidant component, whether it contains oneantioxidant or a mixture of two or more antioxidants, may be present inthe overall composition from 0.05 to 13 pbw, or from 0.1 to 0.4 pbw, orfrom 0.05, 0.1, 0.2, or 0.3 up to 13, 0.9, 0.75, 0.6, or 0.5 pbw. Insome embodiments the antioxidant component is even present from 0.4 upto 0.9 or 0.5 pbw. In other embodiments the antioxidant component ispresent from 0.45, 0.465, or even 0.60 up to 0.87, 0.865, 0.70 or 0.65pbw.

The Dispersant Component

The dispersant component includes: (i) a polyetheramine; (ii) a boratedsuccinimide dispersant; (iii) a non-borated succinimide dispersant; (iv)a Mannich reaction product of a dialkylamine, an aldehyde and ahydrocarbyl substituted phenol; or any combination thereof. In someembodiments the dispersant component is present from 0.05 to 0.5 pbw ofthe overall composition.

Polyetheramines of the invention include compounds having two or moreconsecutive ether groups and at least one primary, secondary or tertiaryamino group where the amine nitrogen has some basicity. Thepolyetheramines of this invention include poly(oxyalkylene) amineshaving a sufficient number of repeating oxyalkylene units to render thepoly(oxyalkylene)amine soluble in a base oil while allowing acceptableperformance in ASTM D1401 (Standard Test Method for Water Separabilityof Petroleum Oils and Synthetic Fluids) test. Generally,poly(oxyalkylene)amines having at least about 5 oxyalkylene units aresuitable for use in the present invention. Poly(oxyalkylene)amines caninclude: hydrocarbylpoly(oxyalkylene)amines,hydrocarbylpoly(oxyalkylene)polyamines, and derivatives of polyhydricalcohols having at least two poly(oxyalkylene)amine and/orpoly(oxyalkylene)polyamine chains on the molecule of the derivative. Inone embodiment, the poly(oxyalkylene)amine for use in the invention isrepresented by the formula R—O-(AO)_(m)—R¹—N—R²R³ wherein R is ahydrocarbyl group of 1 to 50 carbon atoms, or about 8 to about 30 carbonatoms; A is an alkylene group having 2 to 18 carbon atoms or 2 to 6carbon atoms; m is a number from 1 to 50; R¹ is an alkylene group having2 to 18 carbon atoms or 2 to 6 carbon atoms; and R² and R³ areindependently hydrogen, a hydrocarbyl group or —[R⁴N(R⁵)]_(n)R⁶ whereinR⁴ is an alkylene group having 2 to 6 carbon atoms, R⁵ and R⁶ areindependently hydrogen or a hydrocarbyl group, and n is a number from 1to 7.

In another embodiment, the poly(oxyalkylene)amine of the presentinvention can be represented by the formula:RO[CH₂CH(CH₂CH₃)O]_(m)CH₂CH₂CH₂NH₂ wherein R is an aliphatic group oralkyl-substituted phenyl group of 8 to 30 carbon atoms; and m is anumber from 12 to 30. In yet another embodiment, thepoly(oxyalkylene)amine of the present invention can be represented bythe formula:CH₃CH(CH₃)[CH₂CH(CH₃)]₂CH(CH₃)CH₂CH₂O—[CH₂CH(CH₂CH₃)O]_(m)CH₂CH₂CH₂NH₂wherein m is a number from about 16 to about 28. Poly(oxyalkylene)aminesof the present invention can have a molecular weight in the range fromabout 300 to about 5,000.

The polyetheramines of the present invention can be prepared byinitially condensing an alcohol or alkylphenol with an alkylene oxide,mixture of alkylene oxides or with several alkylene oxides in sequentialfashion in a 1:1-50 mole ratio of hydric compound to alkylene oxide toform a polyether intermediate. U.S. Pat. Nos. 5,112,364 and 5,264,006provide reaction conditions for preparing a polyether intermediate.

The alcohols can be monohydric or polyhydric, linear or branched,saturated or unsaturated and having 1 to 50 carbon atoms, or from 8 to30 carbon atoms, or from 10 to 16 carbon atoms. Branched alcohols of thepresent invention can include Guerbet alcohols, as described in U.S.Pat. No. 5,264,006, which generally contain between 12 and 40 carbonatoms and can be represented by the formula R—CH(CH₂CH₂R)CH₂OH where Ris a hydrocarbyl group. In one embodiment, the alkyl group of thealkylphenols can be 1 to 50 carbon atoms, or 2 to 24 carbon atoms, or 10to 20 carbon atoms.

In one embodiment, the alkylene oxides include 1,2-epoxyalkanes having 2to 18 carbon atoms, or 2 to 6 carbon atoms. In yet another embodiment,the alkylene oxides can be ethylene oxide, propylene oxide and butyleneoxide. Especially useful is propylene oxide, butylene oxide, or amixture thereof. The number of alkylene oxide derived units in thepolyether intermediate can be 1-50, or 12-30, or 16-28.

The polyether intermediates can be converted to polyetheramines byseveral methods. The polyether intermediate can be converted to apolyetheramine by a reductive amination with ammonia, a primary amine ora polyamine as described in U.S. Pat. Nos. 5,112,364 and 5,752,991. Inone embodiment, the polyether intermediate can be converted to apolyetheramine via an addition reaction of the polyether toacrylonitrile to form a nitrile which is then hydrogenated to form thepolyetheramine. U.S. Pat. No. 5,264,006 provides reaction conditions forthe cyanoethylation of the polyether with acrylonitrile and thesubsequent hydrogenation to form the polyetheramine. In yet anotherembodiment, the polyether intermediate or poly(oxyalkylene) alcohol isconverted to the corresponding poly(oxyalkylene) chloride via a suitablechlorinating agent followed by displacement of chlorine with ammonia, aprimary or secondary amine, or a polyamine as described in U.S. Pat. No.4,247,301.

In some embodiments the polyetheramine of the present invention isderived from the reaction of a mixture of alcohols containing from 10 to18 carbon atoms, an alkoxylate and an amine.

In some embodiments the compositions of the present invention include apolyetheramine dispersant where the polyetheramine is present in theoverall composition from 0.07 to 0.6 pbw, or from 0.09 to 0.5 pbw.

In addition, in some of these embodiments, (i) the antioxidant componentis present in the overall composition at less than 0.865 pbw; (ii) thecomposition is free of N-alkyl sarcosines; (iii) the compositioncontains less than 0.15 pbw of fatty carboxylic acids; or anycombination thereof.

Another type of dispersant, which can be used in the invention, is asuccinimide. Succinimide dispersants are well known in the field oflubricants and include primarily what are sometimes referred to as“ashless” dispersants because they do not contain ash-forming metals andthey do not normally contribute any ash forming metals when added to alubricant. Succinimide dispersants are the reaction product of ahydrocarbyl substituted succinic acylating agent and an amine containingat least one hydrogen attached to a nitrogen atom. The term “succinicacylating agent” refers to a hydrocarbon-substituted succinic acid orsuccinic acid-producing compound (which term also encompasses the aciditself). Such materials typically include hydrocarbyl-substitutedsuccinic acids, anhydrides, esters (including half esters) and halides.

Succinic based dispersants have a wide variety of chemical structuresincluding typically structures such as:

In the above structure, each R¹ is independently a hydrocarbyl group,which may be bound to multiple succinimide groups, typically apolyolefin-derived group having a number average molecular weight (Mn)of 500 or 700 to 10,000. Typically the hydrocarbyl group is an alkylgroup, frequently a polyisobutylene group derived from polyisobutylenewith a Mn of 500 or 700 to 5000, or 1500 or 2000 to 5000. Alternativelyexpressed, the R¹ groups can contain 40 to 500 carbon atoms or at least50 to 300 carbon atoms, e.g., aliphatic carbon atoms. The R² arealkylene groups, commonly ethylene (C₂H₄) groups. Such molecules arecommonly derived from reaction of an alkenyl acylating agent with apolyamine, and a wide variety of linkages between the two moieties ispossible beside the simple imide structure shown above, including avariety of amides and quaternary ammonium salts. Succinimide dispersantsare more fully described in U.S. Pat. Nos. 4,234,435, 3,172,892, and6,165,235.

The polyalkenes from which the substituent groups are derived aretypically homopolymers and interpolymers of polymerizable olefinmonomers of 2 to 16 carbon atoms; usually 2 to 6 carbon atoms.

The olefin monomers from which the polyalkenes are derived arepolymerizable olefin monomers characterized by the presence of one ormore ethylenically unsaturated groups (i.e., >C═C<); that is, they aremono-olefinic monomers such as ethylene, propylene, 1-butene, isobutene,and 1-octene or polyolefinic monomers (usually diolefinic monomers) suchas 1,3-butadiene, and isoprene. These olefin monomers are usuallypolymerizable terminal olefins; that is, olefins characterized by thepresence in their structure of the group>C═CH₂. Relatively small amountsof non-hydrocarbon substituents can be included in the polyolefin,provided that such substituents do not substantially interfere withformation of the substituted succinic acid acylating agents. Each R¹group may contain one or more reactive groups, i.e. succinic groups.

The amines which are reacted with the succinic acylating agents to formthe carboxylic dispersant composition can be monoamines or polyamines.In either case they will be characterized by the formula R⁴R⁵NH whereinR⁴ and R⁵ are each independently hydrogen, hydrocarbon,amino-substituted hydrocarbon, hydroxy-substituted hydrocarbon,alkoxy-substituted hydrocarbon, amino, carbamyl, thiocarbamyl, guanyl,or acylimidoyl groups provided that no more than one of R⁴ and R⁵ ishydrogen. In all cases, therefore, they will be characterized by thepresence within their structure of at least one H—N<group. Therefore,they have at least one primary (i.e., H₂N—) or secondary amino (i.e.,H—N<) group. Examples of monoamines include ethylamine, diethylamine,n-butylamine, di-n-butylamine, allylamine, isobutylamine, cocoamine,stearylamine, laurylamine, methyllaurylamine, oleylamine,N-methyl-octylamine, dodecylamine, and octadecylamine.

The polyamines from which the dispersant is derived include principallyalkylene amines conforming, for the most part, to the formula

wherein t is an integer typically less than 10, A is hydrogen or ahydrocarbyl group typically having up to 30 carbon atoms, and thealkylene group is typically an alkylene group having less than 8 carbonatoms. The alkylene amines include principally, ethylene amines,hexylene amines, heptylene amines, octylene amines, other polymethyleneamines. They are exemplified specifically by: ethylene diamine,diethylene triamine, triethylene tetramine, propylene diamine,decamethylene diamine, octamethylene diamine,di(heptamethylene)triamine, tripropylene tetramine, tetraethylenepentamine, trimethylene diamine, pentaethylene hexamine,di(-trimethylene)triamine. Higher homologues such as are obtained bycondensing two or more of the above-illustrated alkylene amines likewiseare useful. Tetraethylene pentamine is particularly useful.

The ethylene amines, also referred to as polyethylene polyamines, areespecially useful. They are described in some detail under the heading“Ethylene Amines” in Encyclopedia of Chemical Technology, Kirk andOthmer, Vol. 5, pp. 898-905, Interscience Publishers, New York (1950).

Hydroxyalkyl-substituted alkylene amines, i.e., alkylene amines havingone or more hydroxyalkyl substituents on the nitrogen atoms, likewiseare useful. Examples of such amines include N-(2-hydroxyethyl)ethylenediamine, N,N′-bis(2-hydroxyethyl)-ethylene diamine,1-(2-hydroxyethyl)piperazine, monohydroxy-propyl)-piperazine,di-hydroxypropyl-substituted tetraethylene pentamine,N-(3-hydroxypropyl)-tetra-methylene diamine, and2-heptadecyl-1-(2-hydroxyethyl)-imidazoline.

Higher homologues, such as are obtained by condensation of theabove-illustrated alkylene amines or hydroxy alkyl-substituted alkyleneamines through amino radicals or through hydroxy radicals, are likewiseuseful. Condensed polyamines are formed by a condensation reactionbetween at least one hydroxy compound with at least one polyaminereactant containing at least one primary or secondary amino group andare described in U.S. Pat. No. 5,230,714 (Steckel).

The succinimide dispersant is referred to as such since it normallycontains nitrogen largely in the form of imide functionality, althoughit may be in the form of amine salts, amides, imidazolines as well asmixtures thereof. To prepare the succinimide dispersant, one or more ofthe succinic acid-producing compounds and one or more of the amines areheated, typically with removal of water, optionally in the presence of anormally liquid, substantially inert organic liquid solvent/diluent atan elevated temperature, generally in the range of 80° C. up to thedecomposition point of the mixture or the product; typically 100° C. to300° C.

The succinic acylating agent and the amine (or organic hydroxy compound,or mixture thereof) are typically reacted in amounts sufficient toprovide at least one-half equivalent, per equivalent of acid-producingcompound, of the amine (or hydroxy compound, as the case may be).Generally, the maximum amount of amine present will be about 2 moles ofamine per equivalent of succinic acylating agent. For the purposes ofthis invention, an equivalent of the amine is that amount of the aminecorresponding to the total weight of amine divided by the total numberof nitrogen atoms present. The number of equivalents of succinicacid-producing compound will vary with the number of succinic groupspresent therein, and generally, there are two equivalents of acylatingreagent for each succinic group in the acylating reagents. Additionaldetails and examples of the procedures for preparing the succinimidedetergents of the present invention are included in, for example, U.S.Pat. Nos. 3,172,892; 3,219,666; 3,272,746; 4,234,435; 6,440,905 and6,165,235.

In some embodiments the compositions of the invention include anon-borated succinimide dispersant derived from polyisobutylene having anumber average molecular weight from 500 to 3000 andpolyethylenepolyamines.

In such embodiments the non-borated succinimide dispersant may bepresent in the overall composition from 0.06 to 0.35 pbw, or from 0.05,0.06, 0.055, 0.065, or even 0.057 up to 0.5, 0.35, 0.33, 0.325, or even0.285 pbw. In some embodiments the non-borated succinimide dispersant ispresent from 0.057 to 0.285 pbw. In other embodiments the non-boratedsuccinimide dispersant is present from 0.057 to 0.325 pbw.

In some of these embodiments the composition contains less than 0.1 pbwof fatty carboxylic acids.

In some embodiments the succinimide dispersants above may be borated.Borated dispersants are well-known materials and can be prepared bytreating one or more of dispersants described above with a boratingagent such as boric acid. Typical conditions include heating thedispersant with boric acid at 100 to 150 degrees C. The dispersants mayalso be treated by reaction with maleic anhydride as described in PCTapplication US99/23940 filed 13 Oct. 1999.

In some embodiments the compositions of the invention include a boratedsuccinimide dispersant derived from polyisobutylene having a numberaverage molecular weight from 500 to 3000 and polyethylenepolyamines.

In such embodiments the borated succinimide dispersant may be present inthe overall composition from 0.07 to 0.4 pbw, or from 0.05, 0.07, oreven 0.067 up to 0.5, 0.4, 0.35 or even 0.335 pbw.

In some of these embodiments the composition contains less than 0.1 pbwof fatty carboxylic acids.

The dispersant of the invention can be a Mannich dispersant. Mannichdispersants are the reaction product of a hydrocarbyl-substitutedphenol, an aldehyde, and an amine or ammonia, but in this inventiongenerally a dialkylamine. The hydrocarbyl substituent of thehydrocarbyl-substituted phenol can have 10 to 400 carbon atoms, inanother instance 30 to 180 carbon atoms, and in a further instance 10 or40 to 110 carbon atoms. This hydrocarbyl substituent can be derived froman olefin or a polyolefin. Useful olefins include alpha-olefins, such as1-decene, which are commercially available.

The polyolefins which can form the hydrocarbyl substituent can beprepared by polymerizing olefin monomers by well known polymerizationmethods and are also commercially available. The olefin monomers includemonoolefins, including monoolefins having 2 to 10 carbon atoms such asethylene, propylene, 1-butene, isobutylene, and 1-decene. An especiallyuseful monoolefin source is a C₄ refinery stream having a 35 to 75weight percent butene content and a 30 to 60 weight percent isobutenecontent. Useful olefin monomers also include diolefins such as isopreneand 1,3-butadiene. Olefin monomers can also include mixtures of two ormore monoolefins, of two or more diolefins, or of one or moremonoolefins and one or more diolefins. Useful polyolefins includepolyisobutylenes having a number average molecular weight of 140 to5000, in another instance of 400 to 2500, and in a further instance of140 or 500 to 1500. The polyisobutylene can have a vinylidene doublebond content of 5 to 69 percent, in a second instance of 50 to 69percent, and in a third instance of 50 to 95 percent. The polyolefin canbe a homopolymer prepared from a single olefin monomer or a copolymerprepared from a mixture of two or more olefin monomers. Also possible asthe hydrocarbyl substituent source are mixtures of two or morehomopolymers, two or more copolymers, or one or more homopolymers andone or more copolymers.

The hydrocarbyl-substituted phenol can be prepared by alkylating phenolwith an olefin or polyolefin described above, such as a polyisobutyleneor polypropylene, using well-known alkylation methods.

The aldehyde used to form the Mannich dispersant can have 1 to 10 carbonatoms, and is generally formaldehyde or a reactive equivalent thereofsuch as formalin or paraformaldehyde.

The amine used to form the Mannich dispersant can be a monoamine or apolyamine, including alkanolamines having one or more hydroxyl groups.Useful amines include ethanolamine, diethanolamine, methylamine,dimethylamine, ethylenediamine, dimethylaminopropylamine,diethylenetriamine and 2-(2-amino-ethylamino) ethanol. The Mannichdispersant can be prepared by reacting a hydrocarbyl-substituted phenol,an aldehyde, and an amine as described in U.S. Pat. No. 5,697,988. Inone embodiment of this invention the Mannich reaction product isprepared from an alkylphenol derived from a polyisobutylene,formaldehyde, and an amine that is a primary monoamine, a secondarymonoamine, or an alkylenediamine, in particular, ethylenediamine ordimethylamine. In some embodiments the Mannich is prepared from adialkylamine or a dialkenylamine.

The Mannich reaction product of the present invention can be prepared byreacting the alkyl-substituted hydroxyaromatic compound, aldehyde andpolyamine by well known methods including the method described in U.S.Pat. No. 5,876,468.

The Mannich reaction product can be prepared by well known methodsgenerally involving reacting the hydrocarbyl substituted hydroxyaromatic compound, an aldehyde and an amine at temperatures between 50to 200° C. in the presence of a solvent or diluent while removingreaction water as described in U.S. Pat. No. 5,876,468.

In some embodiments the compositions of the present invention contain aMannich reaction product derived from the reaction of a dialkylamine,formaldehyde, and a polyisobutylene substituted phenol where thepolyisobutylene has a number average molecular weight from 500 to 3000.The Mannich dispersant may be present in the overall composition from0.07 to 0.44 pbw, from 0.05, 0.07, or even 0.088 up to 0.5, 0.45, oreven 0.44 pbw.

Additional Additives

Optionally the lubricating compositions of the invention include one ormore additional additives, which may be selected from the groupincluding: a foam inhibitor, a demulsifier, a pour point depressant, ormixtures thereof. The optional additives are present in the range from0.0005 to 1.3, from 0.00075 to 0.5, from 0.001 to 0.4, or from 0.0015 to0.3 pbw of the lubricating oil composition. The optional additives maybe used alone or mixtures thereof.

Antifoams, also known as foam inhibitors, are known in the art andinclude but are not limited to organic silicones and non-silicon foaminhibitors. Examples of organic silicones include dimethyl silicone andpolysiloxanes. Examples of non-silicon foam inhibitors include but arenot limited to poly(ethyl acrylate), poly(2-ethylhexylacrylate),copolymers of ethyl acrylate and 2-ethylhexy acrylate and optionallyvinyl acetate, poly vinyl acetate, polyethers, polyacrylates andmixtures thereof. In some embodiments the antifoam is a polyacrylate.Antifoams may be present in the composition from 0.001 to 0.012 or 0.004pbw or even 0.001 to 0.003.

Demulsifiers are known in the art and include but are not limited toderivatives of propylene oxide, ethylene oxide, polyoxyalkylenealcohols, alkyl amines, amino alcohols, diamines or polyamines reactedsequentially with ethylene oxide or substituted ethylene oxides ormixtures thereof. Examples of demulsifiers include polyethylene glycols,polyethylene oxides, polypropylene oxides, (ethylene oxide-propyleneoxide) polymers and mixtures thereof. In some embodiments thedemulsifiers is a polyether. Demulsifiers may be present in thecomposition from 0.002 to 0.012 pbw.

Pour point depressants are known in the art and include but are notlimited to esters of maleic anhydride-styrene copolymers,polymethacrylates; polyacrylates; polyacrylamides; condensation productsof haloparaffin waxes and aromatic compounds; vinyl carboxylatepolymers; and terpolymers of dialkyl fumarates, vinyl esters of fattyacids, ethylene-vinyl acetate copolymers, alkyl phenol formaldehydecondensation resins, alkyl vinyl ethers and mixtures thereof.

The compositions of the invention may also include a rust inhibitor.Suitable rust inhibitors include hydrocarbyl amine salts ofalkylphosphoric acid, hydrocarbyl amine salts of dialkyldithiophosphoricacid, hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acid, fattycarboxylic acids or esters thereof, an ester of a nitrogen-containingcarboxylic acid, an ammonium sulfonate, an imidazoline, or anycombination thereof; or mixtures thereof.

Suitable hydrocarbyl amine salts of alkylphosphoric acid of theinvention are represented by the following formula:

wherein R²¹ and R²² are independently hydrogen, alkyl chains orhydrocarbyl, preferably at least one of R²¹ and R²² are hydrocarbyl. R²¹and R²² contain about 4 to about 30, preferably about 8 to about 25,more preferably about 10 to about 20, and most preferably about 13 toabout 19 carbon atoms. R²³, R²⁴ and R²⁵ are independently hydrogen,alkyl branched or linear alkyl chains with about 1 to about 30,preferably about 4 to about 24, even more preferably about 6 to about20, and most preferably about 10 to about 16 carbon atoms. R²³, R²⁴ andR²⁵ are independently hydrogen, alkyl branched or linear alkyl chains,preferably at least one, and most preferably two of R²³, R²⁴ and R²⁵ arehydrogen.

Examples of alkyl groups suitable for R²³, R²⁴ and R²⁵ include but arenot limited to butyl, sec butyl, isobutyl, tert-butyl, pentyl, n-hexyl,sec hexyl, n-octyl, 2-ethyl, hexyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, octadecenyl,nonodecyl, eicosyl or mixtures thereof.

In one embodiment the hydrocarbyl amine salt of an alkylphosphoric acidis the reaction product of a C₁₄ to C₁₈ alkylated phosphoric acid withPrimene 81R (produced and sold by Rohm & Haas) which is a mixture of C₁₁to C₁₄ tertiary alkyl primary amines.

Hydrocarbyl amine salts of dialkyldithiophosphoric acid of the inventionused in the rust inhibitor package are represented by the formula:

wherein R²⁶ and R²⁷ are independently branched or linear alkyl groups.R²⁶ and R²⁷ contain about 3 to about 30, preferably about 4 to about 25,more preferably about 5 to about 20, and most preferably about 6 toabout 19 carbon atoms. R²³, R²⁴ and R²⁵ are as described above.

Examples of hydrocarbyl amine salts of dialkyldithiophosphoric acid ofthe invention include but are not limited to the reaction product(s) ofheptylated or octylated or nonylated dithiophosphoric acids withethylene diamine, morpholine or Primene 81R or mixtures thereof.

Suitable hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acidsused in the rust inhibitor package of the invention are represented bythe formula:

wherein Cy is a benzene or naphthalene ring. R²⁸ is a hydrocarbyl groupwith about 4 to about 30, preferably about 6 to about 25, morepreferably about 8 to about 20 carbon atoms. z is independently 1, 2, 3,or 4 and most preferably z is 1 or 2. R²³, R²⁴ and R²⁵ are as describedabove.

Examples of hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acidof the invention include but are not limited to the ethylene diaminesalt of dinonyl naphthalene sulphonic acid.

Examples of suitable fatty carboxylic acids or esters thereof includeglycerol monooleate and oleic acid. An example of a suitable ester of anitrogen-containing carboxylic acid includes oleyl sarcosine.

The rust inhibitors may be present in the range from 0.02-0.2, from 0.03to 0.15, from 0.04 to 0.12, or from 0.05 to 0.1 pbw of the lubricatingoil composition. The rust inhibitors of the invention may be used aloneor in mixtures thereof.

The lubricating compositions of the invention may also include a metaldeactivator. Metal deactivators are used to neutralise the catalyticeffect of metal for promoting oxidation in lubricating oil. Suitablemetal deactivators include but are not limited to triazoles,tolyltriazoles, a thiadiazole, or combinations thereof, as well asderivatives thereof. Examples include derivatives of benzotriazoles,benzimidazole, 2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles,2-(N,N′-dialkyldithio-carbamoyl)benzothiazoles,2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles,2,5-bis(N,N′-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles,2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof.

In some embodiments the metal deactivator is a hydrocarbyl substitutedbenzotriazole compound. The benzotriazole compounds with hydrocarbylsubstitutions include at least one of the following ring positions 1- or2- or 4- or 5- or 6- or 7-benzotriazoles. The hydrocarbyl groups containabout 1 to about 30, preferably about 1 to about 15, more preferablyabout 1 to about 7 carbon atoms, and most preferably the metaldeactivator is 5-methylbenzotriazole used alone or mixtures thereof.

In some embodiments the lubricating compositions on the inventioninclude a substituted triazole, and may be a substituted benzotriazole.In some of these embodiments the hydrocarbyl group linked to one of thenitrogen atoms in the triazole ring does not contain any oxygen atoms.

In some embodiments the substituted triazole has a single hydrocarbylgroup linked to a nitrogen atom on the triazole ring. In someembodiments the substituted triazole contains an aryl group linked and asingle hydrocarbyl group linked to a nitrogen atom on the triazole ring.

In some embodiments the substituted triazole may be represented by thefollowing formulas:

or a combination thereof; where, for both formula X and formula XI: n isan integer from 0 to 4; —R is a hydrocarbyl group; —Y is —R¹ or—(R²)_(m)—NR³R³ where —R¹ is a hydrocarbyl group, —R²— is ahydrocarbylene group, m is 0 or 1 or 2, and each —R³ is independentlyhydrogen or a hydrocarbyl group, so long as the —R¹, —R²—, and —R³overall contain from 7 or even 9 to 40 carbon atoms combined. In someembodiments the substituted triazole of the invention is represented byFormula (X).

In some embodiments: n may be from 0 or 1 up to 4, 3, 2 or 1; R may be ahydrocarbyl group and may contain from 1 to 50 carbon atoms, or from 1or 2 up to 40, 30, 20, 18 or even 8 carbon atoms, and in someembodiments contains 1 or 2 carbon atoms; within Y, m may be 0 or 1 or 2and in some embodiments 1 or 2; R¹ may be a hydrocarbyl group and maycontain from 1, 6, 10 or 12 up to 40, 30, 20, or even 18 carbon atoms;R² may be a hydrocarbylene group and may contain from 1, 6, 10 or 12 upto 40, 30, 20, 18, or even 8 carbon atoms or even 1 to 8 carbon atomsand in some embodiments contains 1 carbon atom; R³ may be hydrogen or ahydrocarbyl group and may contain from 1, 6, 10 or 12 up to 40, 30, 20,18, or even 8 carbon atoms or even 1 to 8 carbon atoms and in someembodiments contains 8 carbon atoms, so long as Y contains from 8 to 40carbon atoms.

In some embodiments —Y is —R¹, —R²—NHH, —R²—NHR³, —R²—NR³R³ where thevarious R groups can have any of definitions provided above again solong as the Y group contains overall 6 or 7 or even 9 up to 40 carbonatoms.

In some embodiments all of the hydrocarbyl groups described above arefree of oxygen atoms. In some embodiments all of the hydrocarbyl groupsdescribed above are free of all heteroatoms and are purely alkyl groupsexcept for a single nitrogen atom present in the Y group.

The substituted triazole of the invention may be prepared by condensinga basic triazole via its acidic —NH group with an aldehyde and an amine.In some embodiments the substituted triazole is the reaction product ofa triazole, an aldehyde and an amine. Suitable triazoles that may beused to prepare the substituted triazole of the invention includebenzotriazole, while suitable aldehydes include formaldehyde andreactive equivalents like formalin, while suitable amines includeprimary or secondary amines. In some embodiments the amines aresecondary amines and further are branched amines. In still furtherembodiments the amines are beta-branched amines, for examplesbis-2-ethylhexyl amine.

The metal deactivators may be present in the range from 0.001 to 0.1,from 0.01 to 0.04 or from 0.015 to 0.03 pbw of the lubricating oilcomposition. Metal deactivators may also be present in the compositionfrom 0.002 or 0.004 to 0.02 pbw. The metal deactivator may be used aloneor mixtures thereof.

INDUSTRIAL APPLICATION

The invention further provides a process for the preparation oflubricating oil compositions. The lubricating oil compositions areprepared by the steps comprising: a) mixing and/or dissolving in oneanother an antioxidant component that includes the combination of analkylated diphenylamine, and a substituted hydrocarbyl mono-sulfide, adispersant component which includes at least one of a polyetheramine, aborated succinimide dispersant, a non-borated succinimide dispersant, ora Mannich reaction product of a dialkylamine, an aldehyde and ahydrocarbyl substituted phenol. Optionally one or more additionaladditives may also be mixed into the oil. The materials are mixed untilthe additives are substantially or wholly dissolved, in some embodimentsat elevated temperatures in the range 40° C. to 110° C., or 50° C. to95° C., or even 55° C. to 85° C.; and for a period of time in the range30 seconds to 24 hours, 2 minutes to 8 hours, or 5 minutes to 4 hours;and at pressures in the range 700 mm of Hg to 2000 mm of Hg, 750 mm ofHg to 900 mm of Hg, or 755 mm of Hg to 800 mm of Hg.

The order of addition of the additives is not overly limited. Theoptional additives may be mixed in at the same time as the othercomponents or at a later time using any of the mixing proceduresdescribed above.

In some embodiments a portion of oil or similar diluent is present withthe components and the components are mixed into the oil. In otherembodiments a minimal amount of oil or diluent is present, other thanthat amount inherently present in the additive from their means ofproduction and preparation and additional base oil is added after thecomponent have been mixed. In any event the described processes resultsin lubricating compositions.

In some embodiments the lubricating oil compositions may be preparedfrom a concentrate comprising the steps of: a) mixing all of thecomponents described above with minimal oil and/or diluent present,other than optionally some relatively small amount to allow forreasonable handling properties. The resulting concentrate may then beused in the preparation of a lubricating composition by mixing theconcentrate with an effective amount of base oil or mixtures thereofresulting in a finished fluid. Optional additives may be added to theconcentrate or to the resulting final fluid. These optional additivesinclude any of those described above. In some embodiments these optionaladditives include a foam inhibitor, a demulsifier, a viscosity modifier,a pour point depressant, or mixtures thereof, and may be added such thatthey are present in the overall compositions in the range about 0, 0.01,0.1 or even 0.25 or up to about 13, 10, 8 or even 6 pbw.

The compositions of the present invention may be used as industrialfluids, hydraulic fluids, turbine oils and circulating oils andcombinations thereof. In some embodiments the compositions are used insteam and gas turbine systems. The use of the lubricating oilcomposition in such systems may prevent the formation of filter pluggingdeposits and sludge in turbines, or may provide at least one improvedproperty selected from rust inhibition, oxidation inhibition andmixtures thereof. The invention further provides a lubricating oilcomposition that does not substantially react with zinc and/or calciumwhich may also prevent the formation of sludge and particulate materialthat accumulates, plugging the fine filters.

The invention further provides a method of lubricating a steam or gasturbine comprising the steps of supplying to said turbine any of thelubricating compositions described herein.

The invention further provides a method of improving the cleanliness ofa steam or gas turbine comprising the steps of supplying to said turbineany of the lubricating compositions described herein. Operating theturbine with the described lubricating composition will result inimproved cleanliness compared systems operated with conventionallubricants, particularly those formulated in Group II and Group IIIoils.

Specific Embodiment

The invention will be further illustrated by the following examples,which set forth particularly advantageous embodiments. While theexamples are provided to illustrate the invention, they are not intendedto limit it.

Comparative Example Set

Three comparative examples are prepared in order to better demonstratethe effects of the compositions of the present invention. Thesecomparative examples are then included in each of the example setsbelow. As with all of the examples below, other additives are alsopresent in the various formulations. While differences between exampleformulations are noted, full formulation details are not provided wherethey are not considered critical to the results of the testing and/orwhere the specific details are not believed to impact the results acrosssamples.

Comparative Examples 1, 2 and 3 are each prepared in a blend of GroupIII base oils. This same blend of Group III base oils is used in thepreparation of all of the examples described herein unless otherwisenoted. All the formulations provided below are based on 100 pbw of thebase oil. Comparative Examples 1, 2 and 3 also include a polyetherdemulsifier, an antiwear agent, an antifoam, and a metal deactivator.Comparative Examples 1 and 2 contain the same polyether demulsifierwhile Comparative Example 3 contains a different polyether demulsifier.Comparative Example 1 contains no dispersant, 0.375 pbw alkylateddiphenyl amine antioxidant and 0.09 pbw substituted hydrocarbylmono-sulfide. Comparative Example 2 contains no dispersant, 0.51 pbwalkylated diphenyl amine antioxidant, 0.09 pbw substituted hydrocarbylmono-sulfide, and 0.12 pbw of a sterically hindered phenol antioxidant.Comparative Example 3 contains no dispersant, 0.775 pbw alkylateddiphenyl amine antioxidant and 0.09 pbw substituted hydrocarbylmono-sulfide. The formulation details and test results obtained for thecomparative examples are included in the summary table below for each ofthe example sets.

Example Set 1

A set of examples is prepared where the formulations contain apolyetheramine dispersant. The tables below summarize theseformulations, including the comparative formulations described above.Except for the differences noted in the tables and their footnotes, theformulations of the listed examples are substantially equivalent. Thevalues in the tables are pbw.

TABLE 1-1 Details of Comparative Examples and Examples 1-A to 1-E CompComp Comp Ex Ex Ex Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 1-A⁴ 1-B⁵ 1-C⁶ 1-D⁷1-E⁸ Base Oil Grp III Grp III Grp III Grp III Grp III Grp II Grp II GrpIII Alkylated 0.375 0.510 0.775 0.375 0.375 0.375 0.375 0.775Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09Sulfide Polyetheramine 0.0 0.0 0.0 0.1 0.5 0.5 0.5 0.5 DispersantBorated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Non-Borated 0.0 0.00.0 0.0 0.0 0.0 0.0 0.0 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.00.0 Dispersant ¹Comparative Example 1 also contains a polyetherdemulsifier, an antiwear agent, an antifoam, and metal deactivator inconventional amounts, referred to below as Additive Package I.²Comparative Example 2 also contains Additive Package I. ³ComparativeExample 3 contains the same additives and the same amounts as those inAdditive Package I except that the specific polyether demulsifier isdifferent from that used in the other examples. This set of additives isreferred to as Additive Package II below. ⁴Example 1-A also containsAdditive Package I. ⁵Example 1-B also contains Additive Package I.⁶Example 1-C also contains Additive Package I. ⁷Example 1-D alsocontains Additive Package I. ⁸Example 1-E also contains Additive PackageII.

TABLE 1-2 Details of Examples 1-F to 1-M Ex Ex Ex Ex Ex Ex Ex ExComponent 1-F⁹ 1-G¹⁰ 1-H¹¹ 1-I¹² 1-J¹³ 1-K¹⁴ 1-L¹⁵ 1-M¹⁶ Base Oil BlendGrp III Grp III Grp III Grp III Grp III Grp III Grp III Grp II Alkylated0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 Diphenylamine SubstMono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.50.5 0.5 0.5 0.5 0.5 0.5 0.4 Dispersant Borated 0.0 0.0 0.0 0.0 0.0 0.00.0 0.0 Succinimide Non-Borated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dispersant ⁹Example1-F also contains Additive Package II, as defined in Table 1-1 above.¹⁰Example 1-G contains the polyether demulsifier and metal deactivatorof Additive Package II but does not contain the antiwear agent or theantifoam. This set of additives is referred to as Additive Package IIIbelow. The example also contains a fatty carboxylic acid. ¹¹Example 1-Halso contains Additive Package III and a fatty carboxylic ester.¹²Example 1-I also contains Additive Package III and a sarcosinecorrosion inhibitor. ¹³Example 1-J also contains Additive Package IIIand a fatty carboxylic ester. ¹⁴Example 1-K also contains AdditivePackage III and a sarcosine corrosion inhibitor. ¹⁵Example 1-L alsocontains Additive Package III and a fatty carboxylic acid but in asmaller amount that used in Example 1-G. ¹⁶Example 1-M also containsAdditive Package I.

These examples are evaluated using ASTM D1401 to evaluate each sample'swater separability performance and an internal thermal stability test.

For ASTM D1401, the test procedure involves a sample containing about 40ml of the composition of the invention and about 40 ml of distilledwater where the sample is stirred for about 5 minutes at about 54° C. ina graduated cylinder. The resulting mixture is then left to stand forabout 30 minutes to allow a degree of separation of water and thecomposition of the invention to occur. The amount of separation ismeasured after every 5 minutes of the test. The results reported arebased on X-Y-Z, where X indicates the amount of oil separated out, Yindicates the amount of water separated out and Z indicates the amountof oil and water still in an emulsion. The less time it takes for asample to reach a reported result of 40-40-0, or a result roughlyequivalent thereto, the better its performance.

The thermal stability test used for this testing involves placingstandard sized copper and steel rods, after polishing and weighing, in asample of the example formulation with the rods arranged so that theyare in contact with one another at their midpoint (forming an X). Thesubmerged rods are then held at 135° C.±1° C. for 168 hours. The rodsare then rated for corrosion and weighed. The reported results for thistest include the copper rod corrosion rating, the steel rod corrosionrating, and the amount of sludge generated which is determined byfiltering a 100 mL portion of the oil, rinsing and drying the filter padwith any accumulated deposit; then weighing the dried filter paper andreported in mg per 100 ml. The corrosion ratings are on a scale of 1 to10 with 1 being a freshly polished rod and 10 being a severely corrodedrod. The lower the corrosion ratings and the lower the reported sludge,the better the performance of the sample.

The results of this testing are presented in the tables below. If noresults are listed for a specific sample it indicates the sample was nottested by that method.

TABLE 1-3 Results for Comparative Examples and Examples 1-A to 1-E CompComp Comp Ex Ex Ex Ex Ex Test Method Ex 1 Ex 2 Ex 3 1-A 1-B¹⁷ 1-C 1-D1-E D1401  0 min 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80  5 min 12-6-6226-22-32 10-0-70 5-5-70 1-25-54 10 min 36-36-8 29-40-1 35-26-20 35-30-1540-40-0 15 min 40-40-0 40-40-0 40-40-0 40-40-0 20 min 25 min 30 minTherm Stability Copper Rating 3 5 4 3 3 4 4 Steel Rating 3 8 2 7 1 1 2Sludge (mg/100 ml) 39.8 15.9 26.8 17.75 1.9 3.6 37.6 ¹⁷Example 1-B wastested three times using the D1401 method. In one instance the sampledid not reach a 40-40-0 rating in 30 minutes. In one instance the samplereached a 40-40-0 rating in 15 minutes. In one instance the samplereached a 40-40-0 rating in 10 minutes. The middle result is reported inthe table above and is expected to be a fair representation of thesample's performance.

TABLE 1-4 Results for Examples 1-F to 1-M Ex Ex Ex Ex Ex Ex Ex Ex TestMethod 1-F 1-G 1-H 1-I 1-J 1-K 1-L 1-M D1401  0 min 0-0-80 0-0-80 0-0-800-0-80 0-0-80 0-0-80 0-0-80 0-0-80  5 min 37-39-4 3-40-2 10-2-68 2-25-537-0-73 1-0-79 2-0-78 35-35-10 10 min 38-40-2 40-40-0 29-20-31 2-27-5130-27-23 1-0-79 4-0-76 39-40-1 15 min 39-40-1 40-40-0 3-28-49 40-40-01-0-79 7-11-62 39-40-1 20 min 39-40-1 5-30-45 1-0-79 7-20-53 39-40-1 25min 39-40-1 9-30-41 1-0-79 30-38-12 39-40-1 30 min 39-40-1 19-32-291-0-79 38-38-4 39-40-1 Therm Stability Copper Rating 3 3 4 3 4 5 SteelRating 1 1 1 1 2 1 Sludge (mg/100 ml) 3.7 19.5 2.8 3.4 1.7 2.8

The results show that the compositions of the invention give improvedthermal stability protection while also maintaining acceptable waterseparability. In some embodiments the invention provides both improvedthermal stability and water separability.

Example Set 2

A set of examples is prepared where the formulations contain a boratedsuccinimide dispersant. The tables below summarize these formulations,including the comparative formulations described above. Except for thedifferences noted in the tables and their footnotes, the formulations ofthe listed examples are substantially equivalent. The values in thetables are pbw.

TABLE 2-1 Details of Comparative Examples and Examples 2-A to 2-E CompComp Comp Ex Ex Ex Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 2-A⁴ 2-B⁵ 2-C⁶ 2-D⁷2-E⁸ Base Oil Grp III Grp III Grp III Grp III Grp III Grp III Grp IIIGrp III Alkylated 0.375 0.510 0.775 0.375 0.375 0.375 0.375 0.375Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09Sulfide Polyetheramine 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 DispersantBorated 0.0 0.0 0.0 0.1 0.5 0.1 0.1 0.1 Succinimide Non-Borated 0.0 0.00.0 0.0 0.0 0.0 0.0 0.0 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.00.0 Dispersant ¹See details for Comparative Example 1 above. ²Seedetails for Comparative Example 2 above. ³See details for ComparativeExample 3 above. ⁴Example 2-A also contains Additive Package I, asdefined above. ⁵Example 2-B also contains Additive Package I. ⁶Example2-C also contains Additive Package I and a fatty carboxylic acid.⁷Example 2-D also contains Additive Package I and a fatty carboxylicester. ⁸Example 2-E also contains Additive Package I and a sarcosinecorrosion inhibitor.

TABLE 2-2 Details of Examples 2-F to 2-H Ex Ex Ex Component 2-F⁹ 2-G¹⁰2-H¹¹ Base Oil Grp III Grp II Grp II Alkylated 0.375 0.375 0.375Diphenylamine Subst Mono- 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.00.0 Dispersant Borated 0.25 0.25 0.25 Succinimide Non-Borated 0.0 0.00.0 Succinimide Mannich 0.0 0.0 0.0 Dispersant ⁹Example 2-F alsocontains Additive Package I. ¹⁰Example 2-G also contains AdditivePackage I except that the level of metal deactivator in the package isreduced. ¹¹Example 2-H has the same additive package as Example 2-G.

These examples are evaluated using ASTM D1401 to evaluate each sample'swater separability performance and an internal thermal stability test,as described in the sections above. The results of this testing arepresented in the tables below. If no results are listed for a specificsample it indicates the sample was not tested by that method.

TABLE 2-3 Results for Comparative Examples and Examples 2-A to 2-E CompComp Comp Ex Ex Ex Ex Ex Test Method Ex 1 Ex 2 Ex 3 2-A 2-B 2-C 2-D 2-ED1401  0 min 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80  5 min 2-0-78 1-0-795-5-70 30-22-28 0-27-53 10 min 4-9-67 1-0-79 40-40-0 40-40-0 0-37-43 15min 4-36-40 1-0-79 41-39-0 20 min 40-40-0 1-0-79 41-39-0 25 min 1-0-7941-39-0 30 min 1-0-79 41-39-0 Therm Stability Copper Rating 3 5 4 3 4 55 6 Steel Rating 3 8 2 1 1 1 1 1 Sludge (mg/100 ml) 39.8 15.9 26.8 0.10.5 0.1 5.2 1.1

TABLE 2-4 Results for Examples 2-F to 2-H Ex Ex Ex Test Method 2-F 2-G2-H D1401  0 min 0-0-80 0-0-80 0-0-80  5 min 5-5-70 5-0-75 3-5-72 10 min20-22-38 16-10-54 3-5-72 15 min 34-35-11 27-17-36 15-15-50 20 min40-40-0  37-32-11 30-26-24 25 min 40-40-0  37-40-3  30 min 37-10-3 Therm Stability Copper Rating 5 Steel Rating 1 Sludge (mg/100 ml) 12.3

The results show that the compositions of the invention give improvedthermal stability protection while also maintaining acceptable waterseparability. In some embodiments the invention provides both improvedthermal stability and water separability.

Example Set 3

A set of examples is prepared where the formulations contain anon-borated succinimide dispersant. The tables below summarize theseformulations, including the comparative formulations described above.Except for the differences noted in the tables and their footnotes, theformulations of the listed examples are substantially equivalent. Thevalues in the tables are pbw.

TABLE 3-1 Details of Comparative Examples and Examples 3-A to 3-E CompComp Comp Ex Ex Ex Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 3-A⁴ 3-B⁵ 3-C⁶ 3-D⁷3-E⁸ Base Oil Grp III Grp III Grp III Grp III Grp III Grp III Grp IIIGrp III Alkylated 0.375 0.510 0.775 0.375 0.375 0.775 0.775 0.375Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09Sulfide Polyetheramine 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 DispersantBorated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Non Borated 0.0 0.00.0 0.1 0.5 0.5 0.5 0.5 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.00.0 Dispersant ¹See details for Comparative Example 1 above. ²Seedetails for Comparative Example 2 above. ³See details for ComparativeExample 3 above. ⁴Example 3-A also contains Additive Package I, asdefined above. ⁵Example 3-B also contains Additive Package I. ⁶Example3-C also contains Additive Package II, as defined above. ⁷Example 3-Dalso contains Additive Package II and a fatty carboxylic acid. ⁸Example3-E also contains Additive Package I and a sarcosine corrosioninhibitor.

TABLE 3-2 Details of Examples 3-F to 3-J Ex Ex Ex Ex Ex Component 3-F⁹3-G¹⁰ 3-H¹¹ 3-I¹² 3-J¹³ Base Oil Grp III Grp III Grp III Grp III Grp IIIAlkylated 0.775 0.775 0.375 0.375 0.375 Diphenylamine Subst Mono- 0.090.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.0 0.0 0.0 0.0Dispersant Borated 0.0 0.0 0.0 0.0 0.0 Succinimide Non-Borated 0.5 0.250.25 0.1 0.5 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 Dispersant ⁹Example3-F also contains the antifoam, polyether demulsifier, and metaldeactivator of Additive Package II, as defined above, but does notcontain the antiwear agent. This set of additives is referred to asAdditive Package IV below. The example also contains a fatty carboxylicacid but at a lower level than Example 3-D. ¹⁰Example 3-G containsAdditive Package IV and also contains a fatty carboxylic acid at thesame level as Example 3-D. ¹¹Example 3-H also Additive Package I and asarcosine corrosion inhibitor. ¹²Example 3-I also contains AdditivePackage I and the non-borated succinimide dispersant has a highermolecular weight than that used on the other examples. ¹³Example 3-Jalso contains Additive Package I and uses the higher molecular weightnon-borated succinimide dispersant of Example 3-I.

These examples are evaluated using ASTM D1401 to evaluate each sample'swater separability performance and an internal thermal stability test,as described in the sections above. The results of this testing arepresented in the tables below. If no results are listed for a specificsample it indicates the sample was not tested by that method.

TABLE 3-3 Results for Comparative Examples and Examples 3-A to 3-E CompComp Comp Ex Ex Ex Ex Ex Test Method Ex 1 Ex 2 Ex 3 3-A 3-B 3-C 3-D 3-ED1401  0 min 0-0-80 0-0-80 0-0-80 0-0-80  5 min 0-5-75 0-0-80 0-0-802-0-78 10 min 40-40-0 0-3-77 0-0-80 30-23-27 15 min 23-30-27 10-15-5539-40-1 20 min 40-40-0 36-32-12 40-40-1 25 min 39-40-1 30 min 40-40-0Therm Stability Copper Rating 3 5 4 3 3 3 7 4 Steel Rating 3 8 2 1 1 1 11 Sludge (mg/100 ml) 39.8 15.9 26.8 0.6 1.1 7.5 2.4 3.3

TABLE 3-4 Results for Examples 3-F to 3-J Ex Ex Ex Ex Ex Test Method 3-F3-G 3-H 3-I 3-J D1401  0 min 0-0-80  0-0-80  5 min 2-12-66 0-0-80 10 min5-32-43 1-0-79 15 min 40-40-0  1-0-79 20 min 1-0-79 25 min 1-0-79 30 min1-0-79 Therm Stability Copper Rating 4 4 4 Steel Rating 1 1 1 Sludge(mg/100 ml) 0.4 8.0 0.1

The results show that the compositions of the invention give improvedthermal stability protection while also maintaining acceptable waterseparability. In some embodiments the invention provides both improvedthermal stability and water separability.

Example Set 4

A set of examples is prepared where the formulations contain a Mannichreaction product of a dialkylamine, an aldehyde and a hydrocarbylsubstituted phenol. The tables below summarize these formulations,including the comparative formulations described above. Except for thedifferences noted in the tables and their footnotes, the formulations ofthe listed examples are substantially equivalent. The values in thetables are pbw.

TABLE 4-1 Details of Comparative Examples and Examples 4-A to 4-B CompComp Comp Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 3-A⁴ 3-B⁵ Base Oil Grp IIIGrp III Grp III Grp III Grp III Alkylated 0.375 0.510 0.775 0.375 0.375Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 SulfidePolyetheramine 0.0 0.0 0.0 0.0 0.0 Dispersant Borated 0.0 0.0 0.0 0.00.0 Succinimide Non-Borated 0.0 0.0 0.0 0.0 0.0 Succinimide Mannich 0.00.0 0.0 0.1 0.5 Dispersant ¹See details for Comparative Example 1 above.²See details for Comparative Example 2 above. ³See details forComparative Example 3 above. ⁴Example 4-A also contains Additive PackageI, as defined above. ⁵Example 4-B also contains Additive Package I.

These examples are evaluated using ASTM D1401 to evaluate each sample'swater separability performance and an internal thermal stability test,as described in the sections above. The results of this testing arepresented in the tables below. If no results are listed for a specificsample it indicates the sample was not tested by that method.

TABLE 4-2 Results for Comparative Examples and Examples 4-A to 4-B CompComp Comp Ex Ex Test Method Ex 1 Ex 2 Ex 3 4-A 4-B D1401  0 min  0-0-80 5 min  34-34-12 10 min 39-40-1 15 min 40-40-0 20 min 25 min 30 minTherm Stability Copper Rating 3 5 4 4 Steel Rating 3 8 2 4 Sludge(mg/100 ml) 39.8 15.9 26.8 14.0

The results show that the compositions of the invention give improvedthermal stability protection while also maintaining acceptable waterseparability. In some embodiments the invention provides both improvedthermal stability and water separability.

While the invention has been explained, it is to be understood thatvarious modifications thereof will become apparent to those skilled inthe art upon reading the specification. Therefore, it is to beunderstood that the invention disclosed herein is intended to cover suchmodifications as fall within the scope of the appended claims.

In this specification the terms “hydrocarbyl substituent” or“hydrocarbyl group,” as used herein are used in their ordinary sense,which is well-known to those skilled in the art. Specifically, theyrefer to a group primarily composed of carbon and hydrogen atoms that isattached to the remainder of the molecule through a carbon atom and doesnot exclude the presence of other atoms or groups in a proportioninsufficient to detract from the molecule having a predominantlyhydrocarbon character. In general, no more than two, preferably no morethan one, non-hydrocarbon substituent will be present for every tencarbon atoms in the hydrocarbyl group; typically, there will be nonon-hydrocarbon substituents in the hydrocarbyl group. A more detaileddefinition of the terms “hydrocarbyl substituent” or “hydrocarbylgroup,” is described in U.S. Pat. No. 6,583,092.

Each of the documents referred to above is incorporated herein byreference. Except in the Examples, or where otherwise explicitlyindicated, all numerical quantities in this description specifyingamounts of materials, reaction conditions, molecular weights, number ofcarbon atoms, and the like, are to be understood as modified by the word“about.” Unless otherwise indicated, all percent and formulation valueslisted herein are on a weight basis. Unless otherwise indicated, eachchemical or composition referred to herein should be interpreted asbeing a commercial grade material which may contain the isomers,by-products, derivatives, and other such materials which are normallyunderstood to be present in the commercial grade. However, the amount ofeach chemical component is presented exclusive of any solvent ordiluent, which may be customarily present in the commercial material,unless otherwise indicated. It is to be understood that the upper andlower amount, range, and ratio limits set forth herein may beindependently combined. Similarly, the ranges and amounts for eachelement of the invention can be used together with ranges or amounts forany of the other elements. As used herein, the expression “consistingessentially of” permits the inclusion of substances that do notmaterially affect the basic and novel characteristics of the compositionunder consideration.

1. A lubricating oil composition comprising: a) an oil of lubricatingviscosity comprising a Group II base oil, a Group III base oil, orcombinations thereof; b) an antioxidant component comprising: (i) analkylated diphenylamine, and (ii) a substituted hydrocarbylmono-sulfide; c) a dispersant component comprising at least one of: (i)a polyetheramine, (ii) a borated succinimide dispersant, (iii) anon-borated succinimide dispersant, (iv) a Mannich reaction product of adialkylamine, an aldehyde and a hydrocarbyl substituted phenol; and d)optionally one or more additional additives.
 2. The composition of claim1 wherein component d) comprises a rust inhibitor, a metal deactivator,a demulsifier, an antifoam agent, or combinations thereof.
 3. Thecomposition of claim 1 wherein component b) is present in the overallcomposition from 0.1 to 0.9 parts by weight and component c) is presentin the overall composition from 0.05 to 0.5 parts by weight.
 4. Thecomposition of claim 2 wherein the rust inhibitor comprises an aminephosphate, a fatty carboxylic acid or ester thereof, an ester of anitrogen-containing carboxylic acid, an ammonium sulfonate, animidazoline, or combinations thereof; wherein the metal deactivatorcomprises a triazole, a tolyltriazole, a thiadiazole, or combinationsthereof; wherein the demulsifier comprises a polyether; and wherein theantifoam comprises an acrylate copolymer.
 5. The composition of claim 1,wherein the alkylated diphenylamine is represented by the formula:

wherein R¹ and R² are independently a hydrogen or an alkyl groupcontaining about 5 to 20 carbon atoms; or a linear or branched alkylgroup containing 1 to 24 carbon atoms and q and r are each independently0, 1, 2, or 3, provided that the sum of q and r is at least one.
 6. Thecomposition of claim 1 wherein the substituted hydrocarbyl mono-sulfidesare represented by the formula:

wherein R³ is a saturated or unsaturated branched or linear alkyl groupwith about 8 to about 20 carbon atoms; R⁴, R⁵, R⁶ and R⁷ areindependently hydrogen or alkyl containing about 1 to about 3 carbonatoms.
 7. The composition of claim 6, wherein the substitutedhydrocarbyl monosulfide is n-dodecyl 2-hydroxyethyl sulfide,1-(tert-dodecylthio)-2-propanol, or mixtures thereof.
 8. The compositionof claim 1 wherein the dispersant component comprises a polyetheraminederived from the reaction of a mixture of alcohols containing from 10 to18 carbon atoms, an alkoxylate and an amine; wherein the antioxidantcomponent is present in the overall composition at less than 0.865 partsby weight; wherein the composition is free of N-alkyl sarcosines;wherein the composition contains less than 0.1 parts by weight of fattycarboxylic acids; and wherein the dispersant component is present in theoverall composition from 0.07 to 0.4 parts by weight.
 9. The compositionof claim 1 wherein the dispersant component comprises a boratedsuccinimide dispersant derived from polyisobutylene having a numberaverage molecular weight from 500 to 3000 and polyethylenepolyamines;wherein the dispersant component is present in the overall compositionfrom 0.07 to less than 0.4 parts by weight.
 10. The composition of claim1 wherein the dispersant component comprises a non-borated succinimidedispersant derived from polyisobutylene having a number averagemolecular weight from 500 to 3000 and polyethylenepolyamines; whereinthe composition contains less than 0.1 parts by weight of fattycarboxylic acids; and wherein the dispersant component is present in theoverall composition from 0.06 to 0.35 parts by weight.
 11. Thecomposition of claim 1 wherein the dispersant component comprises aMannich reaction product derived from the reaction of a dialkylamine,formaldehyde, and a polyisobutylene substituted phenol where thepolyisobutylene has a number average molecular weight from 500 to 3000;and wherein the dispersant component is present in the overallcomposition from 0.07 to 0.44 parts by weight.
 12. The lubricatingcomposition of claim 1, wherein the metal deactivator is selected fromthe group comprising hydrocarbyl substituted benzotriazole,5-methylbenzotriazole and mixtures thereof.
 13. The composition of claim1, wherein the additive components b) to d) are in the range about 0 toabout 13 parts by weight of the overall composition.
 14. A process toprepare a lubricating oil composition comprising the steps of: (I)mixing together: a) an oil of lubricating viscosity comprising a GroupII base oil, a group III base oil, or combinations thereof; b) anantioxidant component comprising: (i) an alkylated diphenylamine, and(ii) a substituted hydrocarbyl mono-sulfide; c) a dispersant componentcomprising at least one of: (i) a polyetheramine, (ii) a boratedsuccinimide dispersant, (iii) a non-borated succinimide dispersant, (iv)a Mannich reaction product of a dialkylamine, an aldehyde and ahydrocarbyl substituted phenol; d) optionally other additives.
 15. Theprocess of claim 14, wherein the antioxidant package is in the range of0.05 to 13 parts by weight of the overall composition; the dispersantcomponent is in the range of 0.05 to 10 parts by weight of the overallcomposition; the optional additives, when present, are present from0.001 to 10 parts by weight of the overall composition; and the balanceis made up of the oil of lubricating viscosity.